Provides a selectable time interval between defrost cycles.
It will allow heat for the selected 30/60/90 minute period and provide a 10 minute defrost.
A hold input permits the timer to accumulate time only while the compressor is running.
Additionally, a warm coil causes the disc sensor to open which will prevent time accumulation or end in an in-progress defrost period.
When the defrost period ends either by opening the DFT or after the 10 minute defrost period has elapsed, the timer is reset.

SEQUENCE OF OPERATION: •During Heating the “Y” terminal is energized, & the time logic is energized. •Timer tracks compressor run time to the interval selected. 30/50/90. •When timer sequence is reached, logic checks the status of the defrost thermostat. If the DFT is open, unit does not need defrosting and the timer is reset. • •IF DFT is closed, reversing valve is energized, the outdoor fan is turned off, and the strip heat is turned on.(W2). • •Maximum of 10 minutes or until the DFT opens. • •Defrost sequence configured in the field for 30, 50, and 90 minutes (factory/default set 90 min.)

FORCED DEFROST:•Jumper the R to DFT terminal on the board • •Short the speed up terminal together until the units goes into defrost • •As soon as defrost is started remove your jumper from the speed up terminals or the 10 minute defrost will be shorted to 10 seconds • •Defrost will stop when 10 minutes has past or as soon as the DFT jumper is removed.